The tragedy is wealth polarization
The tragedy of the commons is how Francis Fukuyama describes the infeasibility of Utopia in his new book, The Origins of Political Order. When Garrett Hardin used the phrase as a title for his article in 1968, he actually talked about the dilemma: When everybody owns something, nobody owns it.
We Chinese have a similar saying to describe almost the same thing: A monk fetches water in buckets hanging from a bamboo pole on his shoulder; when he is joined by another monk, he shares the burden with him, but when a third monk joins them, they try to shift the responsibility to each other and as a result, they don't have any water to drink. Simply put, when something is everyone's responsibility, it is nobody's responsibility.
This logic has been used to justify private ownership of property or distinction of property rights or individual responsibility since every human being is assumed to be selfish. But when everyone is busy fulfilling his or her own self-interest, the limited common resources will ultimately be depleted.